石灰石-石膏湿法脱硫系统改造

某电厂300 MW机组由于燃用煤种与设计煤种差别很大,其实际燃煤的含硫量远远超过设计值,造成烟气中SO2排放量成倍增加,不能达标排放,需对其已有脱硫系统进行技术改造,主要是对吸收塔、氧化空气系统、石膏脱水、石灰石浆液供给系统、事故浆液排放系统进行了扩容改造。吸收塔浆液池增高壳体采用塔内立杆倒拉的方法进行顶升安装,上部1.8 m层喷淋层壳体采用吊装。改造后实际运行表明:脱硫率超过96%的设计值,其他指标均达到设计要求,工程改造后每年减排SO2 6.4万t,减排粉尘358 t,每年可节省排污费支出4 032万元,具有显著的社会和经济效益。

THE RETROFIT OF WET LIMESTONE-GYPSUM FGD SYSTEM

As the coal used by the 300MW unit of a power plant is greatly different from the coal designed,the actual sulfur content of the coal is far more than the design value,resulting in SO2 emission of the flue gas increasing by leaps and bounds,which can not meet the emission standards.Therefore it is necessary to reform the existing FGD system.An expansion reform is given to the obsorber,oxidation air system,gypsum dewatering system,limestone slurry supply system and emergency slurry drainage system.For the absorber slurry sump shell whose height is increased,an inversion installation method is adopted,i.e.installed first from the lower part and then to the upper part.The installation of the upper shell of the 1.8 m spray bank added is done by lifting.The actual operation of the reform shows that: the desulfurization rate excesses the design value of 96%,the other values meet the design requirements,annual reduction of SO2 emission reaches 64 thousand tons,dust removal 358 t,annual saving of sewage cost 40.32 million yuan,having a significant social and economic benefit.